Nearly 25 million people in the United States suffer from end-stage lung disease. Lung transplantation, the only curative option for these patients, remains hampered by donor organ shortages, long-term rejection, and the need for immunosuppressive therapy. The ability to generate lungs containing a patient's own cells would radically change the way we currently treat end-stage lung disease. We propose to bioengineer chimeric human lungs by seeding partially decellularized donor lungs with human pluripotent stem cell (hPSC) derived pulmonary progenitors. Our goals are to (1) obtain new insights into hPSC specification towards pulmonary lineages and the formation of lung tissue using native lung matrix, and (2) bioengineer functional lungs for transplantation. We envision that the function of rejected/marginal quality donor lungs can be improved by partial replacement of cellular material by a patient's hPSC-derived pulmonary cells. Our hypothesis is that hPSC-progenitors seeded into the decellularized regions of the lung will be induced to regenerate and remodel the donor lung in response to site-specific signals from the tissue matrix and residual cells. Our approach will be to take donor lungs rejected for transplantation and remove cells from limited regions of the lung while preserving the composition, architecture, and mechanical properties of the decellularized matrix and the surrounding intact parenchyma. By simultaneously perfusing decellularization fluids through the lung parenchyma and Perfadex solution through the portal vein, we will preserve intact lung vasculature. The decellularized regions will then be repopulated by hPSC-derived lung progentor cells to produce a lung that is capable of some minimally acceptable level of gas exchange that will improve upon remodeling. Aim 1 is to derive and fully characterize the different lineages of the lung and airway epithelium from hPSCs. Aim 2 is to bioengineer human lung tissue by hPSC-derived pulmonary cells cultured on slices of decellularized matrix. Aim 3 is to form a chimeric human lung by repopulating decellularized regions of the lung with hPSC- derived pulmonary cells and investigate functional recovery using a clinical lung perfusion system. This proposal ultimately aims to achieve functional recovery of donor lungs rejected for transplantation by combining three major innovative components: (1) Derivation of pulmonary cells from the hPSCs, (2) Regional decellularization of the donor lung with the preservation of vasculature and parenchymal architecture, and (3) Functional recovery through repopulation of the lung with the recipient's cells.